I remember reading some years ago about a study on yawn contagion among apes. The details are a bit fuzzy but I think they established that there was contagion. The article mentioned a possible next step of the study, to find out whether trans-species contagion also occurred: if you see a chimp yawning, will it set you off (or vice versa)? I wonder if they ever got round to that study.
I am a big yawner (hey, the spell checker is not screaming at me, does that mean it's a real word?), and people around me keep complaining about it
Right now, just typing about it makes me want to yawn.